Surgical and like needle and its manufacture



Nov. 26, 1935. N. E. EVERETT SURGICAL AND LIKE NEEDLE AND ITSMANUFACTURE Filed April 24, 1935 Patented Nov. 26, 1935 PATENT OFFICESURGICAL AND LKKE NEEDLE AND ITS MANUFACTURE Norah Elizabeth Everett,London, England Application April 24, 1933, Serial No. 667,697

. In Great Britain March 18, 1933 8 Claims.

This invention relates to improvements in surgical and like needles andto a process for manufacturing the same and like articles of very smallgauge which are hollow at one end. It is extremely difficult, if notimpossible, to produce such small gauge articles by drilling the endthereof, especially with the relatively tough and difiicult metalscommonly used for suture needles. The principal object of the inventionis to provide a simple and inexpensive method of manufacturing suchneedles which does not require particularly skilled or trained labourfor its performance. A further object is to provide suture needles whichcan be produced simply and inexpensively without external roughness orundue weakness at the point where the suture is attached.

With-these objects in view, according to the present invention, suchneedles are manufactured by a method which consists briefly in producingthe same from composite wire comprising a tubular metal shell and ametal core, and in removing the core material from the end part of theneedle. The material of the tubular shell "I: will be chosen to providethe desired characteristics of the final needle. Generally it will comprise a stainless steel, a carbon steel, a nickelchromium alloy oranother alloy which is capable either of being hardened and tempered byheat treatment or of being given a spring temper by cold working. Thecore material will be selected for properties which will facilitate theease of its ultimate removal, for example a metal, alloy or compositionsoluble in acid which does not attack the shell material.

One manner of producing the composite wire will first of all bedescribed by way of example:

A solid billet of the shell material is drilled out to receive a solidbillet of the core material making a push fit therein, a fiux beingcoated upon the outer surface of the core before its introduction, ifdesired. By way of example, the external diameter of the drilled billetmight be and its internal diameter Naturally instead of drilling a solidbillet of the shell material, a tube might be used. The composite billetis reduced to the required diameter by swaging, rolling or drawing. Thismay be followed by a heat treatment which has a dual purpose: Firstly itassists in uniting the core and shell and secondly it may be made to putthe shell in a desired condition, for example, of temper and, if theshell material is susceptible to hardening by heat treatment, ofhardness. Particularly if the shell material is an austenitic steel of,for

example the Staybrite or Contracid varieties, annealing or other heattreatment may be performed in the course of the reduction.

For suture needles, needle lengths, preferably double needle lengths,are next cut from the 5 composite wire and roughly fashioned and bent toa curved shape, if this is required. These steps may, if preferred,precede the heat treatment; A portion of the core material is thenremoved from each end of the double length in 10 one of the mannershereinafter described. For example, and preferably, the core materialmight be dissolved out by a chemical agent which does not attack theshell material. Thus hot concentrated nitric acid can be employed fordissolving a nickel or nickel-silver core out of a Staybrite steelshell. Alternatively the core material might be dissolved out by anelectrolytic action in which said material acts as anode. For instance,a nickel core may be so removed from a shell of stainless steel of theso-called cutlery variety. With these methods, naturally, the solutionprocess is discontinued when the core material has been removed to thedesired depth from the ends of the double needle length.

Instead of chemical actions, mechanical processes may be used. Thus thecore material may be drilled out. For this purpose a relatively softcore material, for instance, a brass core in a carbon steel shell, isused to facilitate the drilling and obviate the difficulty, experiencedhitherto, of satisfactorily drilling such a fine hole in a relativelyhard material. Alternatively, a portion of the core material may bedrawn out. For this purpose, the needle is first squeezed a shortdistance from the end to sever or partially sever the core material.Only a relatively short length of core can be removed by this means, forexample about In this case a core material will be chosen which iscapable of stretching considerably.

The double needle lengths are finally polished, divided and pointed. Afinished needle is illustrated in the drawing in which I is the shell,

2 the core and 3 the longitudinal hole produced at the blunt end by theremoval of the core. The diameter of the core 2 is made such that thehole 3 resulting from its removal is approximately of the same diameteras the suture which it is proposed should be used therewith. The suturemay 5 be secured in the needle by slightly crushing the hollowshell-wall around it with pliers or the like. If the core is ofsufficiently hard material, for example, nickel, the point 6 may beformed thereon, as shown. If, however, the core is of a relatively softmaterial such as brass, the pointing may be performed in such a manneras to form the point on the hard shell to one side of the axis of thecore. Said point may then, if desired, be brought into the axis bysubsequent bending.

A further improvement may be effected by producing as by grinding, oneor more shallow transverse recesses or grooves 4 at the hollow end ofthe needle. This recess or recesses should preferably be deep enough tointersect the central bore 3 and may serve two purposes: In the firstplace the partial weakening where the recess or recesses are providedfacilitates the firm nipping of the hollow needle-end upon the sutureand in the second place a window 5 may be provided through which it canbe seen that the suture is fully introduced into the needle-end beforeit is secured therein. Preferably two such recesses are provided atdiametrically opposite points, as shown.

The above described methods of manufacture may be applied also to sutureneedles of the kind having a terminal slot instead of a hole, forexample as described in the specification of patent application SerialNo. 569,316 (S. J. Everett) filed October 16, 1931. For this purpose itis only necessary, inaddition, to grind away part of the shell-wall ofthe hollow end of the needle, the required slot formation being therebyproduced.

I claim:

1. Small gauge article such as a suture needle, comprising a length ofcomposite wire and consisting of a tubular shell of hard metal and asolid metal core firmly united with said shell but terminating short ofone end thereof to leave said shell hollow at said end;

2. Suture or like small gauge needle, comprising a length of compositewire pointed at one end and consisting of a tubular shell of stainlesssteel and a solid metal core firmly united with said shell butterminating short of the unpointed end to leave said shell hollow atthat end.

3. Suture or like small gauge needle, comprising a length of compositewire pointed at one end and consisting of a tubular shell of hard metaland a solid metal core firmly united with said shell but terminatingshort of the unpointed end to leave said shell hollow at that end forthe reception of a thread, the walls of the hollow end of the shellbeing formed with two diametrically opposed recesses which facilitatenipping of said hollow end to grip the thread.

4. Method of manufacturing a small gauge needle such as a suture needle,comprising producing said needle from a' composite wire consisting of atubular shell of hard metal and. a 1 solid metal core firmly united withsaid shell, and removing the core at one end to leave the shell hollowat said end for the reception of a thread.

5. Method of manufacturing a small gauge needle such as a suture needle,comprising pro- 1 ducing said needle from a composite wire consisting ofa tubular shell of hard stainless basemetal and a solid metal corefirmly united with said shell, and dissolving the core-metal out of theshell at one end to leave said end hollow for 2-: the reception of athread.

6. Method of manufacturing a small gauge needle such as a suture needle,comprising producing said needle from a composite wire consisting of atubular shell of stainless steel and 2 a nickel-silver core firmlyunited with said shell, and removing the core from one end of the shellby dissolving it therefrom with nitric acid to leave said end hollow forthe reception of a 7. Method of manufacturing a smallgaugesneedle-shaped article which is solid for the greater part of its lengthbut is hollow for a substantial length at one end, such as a sutureneedle, comprising producing a composite wire with a sheath 3 of hardmetal appropriate for the exterior of the article and a metal core, andremoving the curemetal from the end of the sheath by the assistance ofchemical action.

8. Method of manufacturing a needle such as 4 a suture needle,comprising producing the needle from a composite wire consisting of ahard metal shell and a metal core, weakening the core at a shortdistance from one end of the needle, and

the shell hollow at that end.

NORAH ELIZABETH EVERETT.

